Nick Clarke was a Radio 4 colossus. He embodied what Radio 4 stands for … and his audience knew and appreciated it. He was fearless, superbly informed, scrupulously impartial, and wonderfully charming.

Every weekday for 13 years on the World at One he probed and challenged his interviewees. He had been doing the same for five years before that on The World This Weekend. His aim was to illuminate the issues that mattered - providing exposition and insight in equal measure - and he had his own unique way of doing it. Nick combined unremitting intellectual courage with unfailing courtesy. Always.

But that wasn't all. He was master of ceremonies for a decade on Radio 4's Round Britain Quiz - where Nick's wide range of interests and considerable brainpower cajoled his contestants towards the answers - with a constant smile in his voice.

And he chaired many editions of Any Questions and Any Answers - where his cultured wit and incisiveness brought the best out of the panellists.

Nick's journalistic hero was Alistair Cooke. Nick wrote his biography - and earlier this year introduced on Radio 4's Book of the Week a previously unpublished Cooke work. Nick had many of the same attributes as his hero. A sublime voice, a mastery of language, an ability to paint a picture with astonishing economy, and above all a connection with the audience.

After his operation last year we all hoped that Nick would give the R4 audience many more years of pleasure. He was unremittingly optimistic and brave and thoughtful. Qualities that he shared with his wife Barbara - with whom he made a compelling Radio 4 documentary about the illness - Fighting to be Normal.

We have lost a supreme champion of Radio 4 - and the BBC. We owe him much.